During constrained path calculation or path re-optimization processes, conventional MPLS- and GMPLS-based traffic engineered transport services use link bandwidth, service expenses, and delay/jitter as traffic engineering (TE) link metrics. However, congestion status of traffic queues in the data plane is not conventionally considered a TE link metric and is not used for constrained path calculation of traffic engineered label switched paths (TE-LSPs). Thus, the impact of congestion in data plane traffic queues is not considered in evaluating the performance, reliability, and availability of transport LSP services in MPLS and GMPLS traffic engineered networks.
However TE links along the LSP's path may sometimes be congested due to faulty hardware and/or software components; due to a denial of service (DOS) attack; and/or due to a transient failure in the network. An LSP re-route over alternate paths and a local repair via protection switching considers link or node failures, however, sometimes traffic congestion through switches in the network occurs when there is no link or node failure (e.g., too much data and not enough transport capacity). Thus, because congestion status of traffic queues is not conventionally considered a TE link metric, no LSP rerouting or local repair occurs on the congested link, causing severe traffic loss.
Accordingly, there are long-felt industry needs for methods and apparatus that improve upon conventional methods and apparatus, including methods and apparatus that mitigate congestion by using advanced traffic engineering services in a MPLS network and/or a GMPLS network.